A population of butterflies has an allele B for big spots on the wings and b for small spots on the wings. The table below provides data about this population. Genotype BB Bb bb
Number of butterflies 300 400 300
Genotype frequency 0.3 0.4 0.3
Regarding these data about the butterfly population, which of the following statements is correct?
A)The population is in Hardy-Weinberg equilibrium because the number of B alleles is equal to the number of b alleles.
B)The population is in Hardy-Weinberg equilibrium because half of the heterozygotes are B and half are b.
C)The population is not in Hardy-Weinberg equilibrium because p² and 2pq are different.
D)The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium.

Question

Quizplus · Accepted Answer

The population is not in Hardy-Weinberg equilibrium because the observed genotype frequencies do not match the expected genotype frequencies. The expected genotype frequencies for a population in Hardy-Weinberg equilibrium can be calculated as follows: 
- p² for BB individuals (0.3 x 0.3 = 0.09)
- 2pq for Bb individuals (2 x 0.3 x 0.4 = 0.24)
- q² for bb individuals (0.4 x 0.4 = 0.16)

The observed genotype frequencies in the given population are different from these expected frequencies, particularly for the bb genotype (which is higher than expected). This indicates that some evolutionary process (such as natural selection, migration, or genetic drift) is likely occurring in this population, causing it to deviate from Hardy-Weinberg equilibrium.

A Population of Butterflies Has an Allele B for Big